In 1996 the Studies of Ocular Complications of AIDS HPMPC Peripheral Cytomegalovirus Retinitis Trial (HPCRT) was completed. It showed that cidofovir (HPMPC) given as an induction at 5mg/kg IV once weekly for two weeks, followed by maintenance at either 5 mg/kg once every two weeks or 3 mg/kg once every two weeks was effective in controlling CMV retinitis. For patients assigned to deferral, the median time-to-progression of the retinitis was 21 days, whereas for those assigned to low-dose cidofovir it was 69 days and to high-dose cidofovir, the median was not reached. The current method of treatment administration using the co-administration of Probenecid and intravenous hydration as well as intermittent dosing minimized but did not completely eliminate nephrotoxicity.